Jiménez-Galán Álvaro, Dixit Gopal, Patchkovskii Serguei, Smirnova Olga, Morales Felipe, Ivanov Misha
Max-Born-Institute, Max-Born Straße 2A, D-12489, Berlin, Germany.
Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
Nat Commun. 2018 Feb 27;9(1):850. doi: 10.1038/s41467-018-03167-2.
High harmonic generation in multi-color laser fields opens the opportunity of generating isolated attosecond pulses with high ellipticity. Such pulses hold the potential for time-resolving chiral electronic, magnetization, and spin dynamics at their natural timescale. However, this potential cannot be realized without characterizing the exact polarization state of light on the attosecond timescale. Here we propose and numerically demonstrate a complete solution of this problem. Our solution exploits the extrinsic two-dimensional chirality induced in an atom interacting with the chiral attosecond pulse and a linearly polarized infrared probe. The resulting asymmetry in the photoelectron spectra allows to reconstruct the complete polarization state of the attosecond pulse, including its possible time dependence. The challenging problem of distinguishing circularly polarized, partially polarized, or unpolarized pulses in the extreme ultraviolet range is also resolved. We expect this approach to become the core ingredient for attosecond measurements of chiral-sensitive processes in gas and condensed phase.
多色激光场中的高次谐波产生为产生具有高椭圆率的孤立阿秒脉冲提供了机会。这种脉冲有潜力在其自然时间尺度上对手性电子、磁化和自旋动力学进行时间分辨。然而，如果不能在阿秒时间尺度上表征光的确切偏振态，就无法实现这一潜力。在此，我们提出并通过数值模拟证明了该问题的一个完整解决方案。我们的解决方案利用了与手性阿秒脉冲和线偏振红外探测光相互作用的原子中诱导的外在二维手性。光电子能谱中产生的不对称性使得能够重建阿秒脉冲的完整偏振态，包括其可能的时间依赖性。在极紫外范围内区分圆偏振、部分偏振或非偏振脉冲这一具有挑战性的问题也得到了解决。我们预计这种方法将成为气体和凝聚相中手性敏感过程阿秒测量的核心要素。
